327 - 11th Botany Textbook Volume 1

Table 1.7: Economic importance of Bacteria
Beneficial aspects Bacteria Role
1. Soil fertility
Ammonification
Nitrification
Nitrogen fixation
2. Antibiotics
1. Bacillus ramosus
2. Bacillus mycoides
1. Nitrobacter
2. Nitrosomonas
1. Azotobacter
2. Clostridium
3. Rhizobium
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Convert complex proteins in the dead
bodies of plants and animals into
ammonia which is later converted into
ammonium salt
Convert ammonium salts into nitrites and
nitrates
(i) Converting atmospheric nitrogen into
organic nitrogen
(ii) The nitrogenous compounds are also
oxidized to nitrogen
(iii) All these activities of bacteria increase
soil fertility
1. Streptomycin Streptomyces griseus It cures urinary infections, tuberculosis,
meningitis and pneumonia
2. Aureomycin Streptomyces aureofaciens It is used as a medicine to treat whooping
cough and eye infections
3. Chloromycetin Streptomyces venezuelae It cure typhoid fever
4. Bacitracin Bacillus licheniformis It is used to treat syphilis
5. Polymyxin Bacillus polymyxa It cure some bacterial diseases
3. Industrial Uses
1. Lactic acid Streptococcus lactis and
Lactobacillus bulgaricus
2. Butter Streptococcus lactis,
Leuconostoc citrovorum
3. cheese Lactobacillus acidophobus,
Lactobacillus lactis
4. Curd Lactobacillus lactis
5. Yoghurt Lactobacillus bulgaricus
6. Vinegar
(Acetic acid)
Acetobacter aceti
Convert milk sugar lactose into lactic acid
Convert milk into butter, cheese, curd and
yoghurt
This bacteria oxidizes ethyl alcohol
obtained from molasses by fermentation
to vinegar(acetic acid)
(Continued)